Plant Health

Why Botanical Oils Work on Whiteflies

Whiteflies are so prevalent on so many crops, growers need to know every tool available to use for control. Development of resistance to conventional insecticides continues to whittle down the number of effective products, even as new ones are introduced. Botanical oils – those made from plant essential oils such as rosemary and mint, have a place in a whitefly program because of the unique benefits they offer. Dr. Murray Isman, Professor of Entomology/Toxicology at The University of British Columbia, lists these benefits as multiple modes of action, short residual activity, less toxicity to bees, zero preharvest interval (PHI),...

Mycorrhiza Key to Plant Health

Beneficial root fungi help plants absorb nutrients more efficiently Sunlight and water are the most obvious, but certainly not the only, factors in plant health. Beneath the soil surface in the tiny space surrounding the plant’s roots, a vital interaction is taking place between the root cells and specialized beneficial fungi called mycorrhiza. There are many types of mycorrhizal fungi, and more than 80% of land plants have symbiotic, or mutually beneficial, associations with them. Most plants depend upon this association for efficient nutrient uptake, and learning how to maximize and support the growth of mycorrhiza can be of...

Systemic Acquired Resistance: Plants’ Secret Weapon

Triggering Plants’ Immune Response Provides Protection Against Disease For nearly a century, plant scientists have known that when a plant survives a disease, it often is more resistant to subsequent infections. It’s as if the plant’s immune system has become stronger, and indeed it has. Because they are rooted in the ground, plants appear to be at the mercy of every disease or insect that comes their way. However, plants actually have a number of defense mechanisms. One of these is systemic acquired resistance (SAR), a whole-plant defensive response to disease. When a pathogen invades, a long-distance chemical signal...

Nutrition at the Root of Plant Health

Seventeen Plant Nutrients You Need to Know There is a delicate balance between too much of a good thing and not enough. Finding the optimum nutrient balance for maximum yield is a perpetual challenge for growers. All plants require 17 essential nutrients for growth. Of these, three (carbon, oxygen and hydrogen) are absorbed through air and water; the rest come from the soil. Determining the proper amount of each required element is a true art, because so many factors come into play including soil pH, soil structure, weather, the species of plant, stage of development, application method, watering needs...

Plant Health Begins at the Soil Level

Fertilizer and lime management must be based on the individual grower’s needs To sustain profitability, growers’ approach to fertilizer and lime management must be based on the unique needs of the farm. Dr. Matt Kleinhenz, associate professor at The Ohio State University, encourages growers to be proactive in managing soils, fertilizer, and lime, reminding them of how critical it is to get quality input from soil testing labs to develop a cohesive soil management plan and increase profitability. “At minimum,” he explained, “it is required [by growers] to maximize the return on ever increasing investments in soil, fertilizer, and...

Foliar Testing Tells the True Story of Plant Nutrition

Accurate leaf sampling produces accurate results, saving money and maximizing yields. Testing for nutrient levels is a process vegetable growers need to undertake to ensure a healthy crop. While the nutrient content of the soil needs to be determined, it also is necessary for growers to conduct foliar testing to find out exactly what is being taken up by the plant. When should testing occur? According to Tim Coolong, assistant professor and Extension vegetable specialist in the Department of Horticulture at the University of Kentucky, at minimum, soil tests should be conducted in the fall for the next growing...

Chelates Bind Essential Nutrients, Keeping Them Available for Plants

Molecules play important role in plant nutrition Making sure that sufficient quantities of essential nutrients are available in the soil is only one component of a plant nutrition program. The nutrients must also be in a form chemically available to the plant. The soil pH, composition, and the presence of other elements can affect the availability of nutrients as well. A type of organic molecule called a chelate may help to make nutrients available that, due to soil conditions, could not otherwise be taken up by the plant. The chelator molecule envelops the ion (magnesium calcium, iron, zinc and...
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